Folding rule



6, 1934- c. M. NICHOLSON 1,979,567

FOLDING RULE Filed June 10, 1932 INVENTOR 63421. M MCHOLSON A4 ATTORNEY Patented Nov. 6, 1934 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to a new and useful improvement in hinge joints and locking means for folding rules and has for its object the provision of a strong, efiicient and simple hinge 8 joint and lock for holding the rule sections in closed position.

A further object includes the provision of a hinge for joining the end section of the rule to the mid section, said hinge having a hinge pin with a socket in one end thereof for engaging a projecting knob of the companion hinge.

Further objects will appear hereinafter and I obtain these objects by a construction illustrated in the accompanying drawing in which Figure 1 is a view in perspective of a rule provided with my improved hinge joint and locking means;

Figs. 2 and 3 show respectively the upper and lower hinge joints of the outer rule sections; Fig. 4 is a sectional view of the knob and socket joints of the rule.

Like reference characters refer to similar parts throughout the several views.

It is one of the purposes of my invention to provide a construction in folding rules whereby the usual locating pins on the mid rule section and on the end sections are replaced by my improved locking means.

It is the purpose of this invention to so construct the locking means that the objections hereinafter applied to the pins will not appear, that is, the locking lugs are so placed and of such a nature as will obviate the objections.

- It is also my purpose to provide a simplified and strengthened mid hinge for the rule which carries a part of the locking device and cooperates therewith.

I further provide hinges for the end sections of a particular construction. In place of the usual hinge pin for this type of hinges I have devised a projecting knob extending from one of the hinge pins and cooperating with a socket 6 on the adjacent hinge to thereby hold the sections in alignment.

As shown in the drawing the rule comprises midsections 3 and 4 connected together by a hinge comprising the similar members 10 and 11 pivotally connected together at 12. The end sections are shown at l and 2 and are pivotally connected together by the hinge structures 22 and 23. It will be noted that the hinge members 22 and 23 are of identical construction and are spaced apart by a sleeve 28. The knob 24 is an extension of the hinge pin 26 and fits into the socket 25 of the hinge pin 27. The diead of knob 24 is of such dimensions that it will removably engage its socket in the pin 27 and is thus snapped and held in closed position.

From the description given it will be apparent that the rule sections are locked together and held in folded position by the lock members. These members are so constructed that although they hold the parts together they will be easily released when it is desired to use the rule.

Having now described my invention, what I claim as new and useful and desire to secure by United States Letters Patent is: 35

In a folding rule having joined mid-sections and end sections, hinge members for foldably uniting the end sections to the mid-sections and means on said hinge members including a knob and socket on the hinge pins of said hinge members for latching the rule sections together.

CARL M. NICHOLSON. 

